How come birds can defy gravity and humans cannot or is there a way to make us fly without an airplane?

Answer 1

They don't.

Nothing does. ;)

But, how do they stay up? They are using the air to hold them up. Still air isn't good for much useful work. But, moving air can be a very powerful thing. Air can move kites, windmills, sailboats, paintballs, trees, houses and cars. It will even blow away your umbrella. Birds are able to harness this power and use it to keep them above the ground. They beat their wings to force the air to move and they can glide at higher elevations by using the existing currents. They have very lightweight bodies and long wingspans compared to their size. When they are flying they hold their bodies horizontally and tuck up their feet to allow the air to flow as smoothly around them as possible. This allows for faster moving, more supportive air.

Try folding paper airplanes in a variety OS shapes to get an idea of what shapes glide well and what shapes don't. This will help you visualise the way a bird's body shape helps the bird to fly.

Answer 2

in my estimation birds dont defy gravity,they resist with their wings.if humans were born with wings,then thats another story my friend